This invention relates to an auxiliary fuel system for vehicles such as fork lift trucks and the like.
Fork lift trucks typically use pressurized tanks filled with propane gas (or natural gas) as a fuel source to operate the internal combustion engine of the vehicle. The use of propane gas or natural gas for such vehicles is desirable in order to reduce or control emissions of combustion products in their useful environment such as warehouses and the like. Typically, a pressurized, propane gas tank is mounted on a lift truck, for example, and attached to a fuel line that, in turn, is connected to the internal combustion engine of the lift truck. The pressurized fuel tank is typically removable and replaceable and includes enough pressurized fuel to operate the truck for a full shift or an eight hour day. However, the operator of the lift truck cannot always predict when and where the fuel in the tank will be consumed and exhausted. Thus, it may be necessary to tow the lift truck back to a refueling center where the empty propane fuel tank is removed and replaced by a full tank. Alternatively, the empty propane fuel tank from the fork lift truck may be removed and carried to a filling station for refilling and return.
In review, on standard fork lift trucks in most warehouses in the United States, the usual fuel utilized by the truck is propane gas and/or natural gas. The gas is provided from a refillable portable tank which is supported or mounted on the truck and which is replaced from time to time as the tank becomes empty. For maximum utilization, a lift truck is operated until its tank becomes empty. At that time, the operator typically removes the empty tank and physically carries it to a storage area where it is exchanged for a full tank and carried back to the lift truck, mounted on the truck, and attached to the proper fuel line. Alternatively, the lift truck can be towed to the fuel tank storage area.
In any event, fuel tank replacement is a time consuming job and may take upwards of thirty minutes in order to complete. Consequently, a system devised to reduce the time for exchanging fillable portable fuel tanks for lift trucks and for other vehicles is desirable. Thus, there has developed a need for an improved fueling system for fork lift trucks and other vehicles such as prime movers, automobiles, trucks and buses, and vehicles of the type which use propane gas or natural gas provided from a pressurized portable or replaceable fuel tank.